Twin Sheet Thermoforming

Twin Sheet Thermoforming

Twin sheet thermoforming has a multitude of benefits, both financially and structurally, for reasons which electronics, automotive, hardware, food and beverage, medical, cosmetics, telecommunications and shipping industries implement these hollow or double-walled components in the packaging of products as well as in the construction of simple and complex parts. Because twin sheet thermoforming creates a hollow shell they are easily employed in applications where thermal or acoustic insulation may be required such as doors, tables and wall panels. Twin sheet thermoformed products are extremely versatile and may be filled with materials or goods or left empty depending upon the application at hand. Twin sheet thermoforming is also a relatively fast, often taking as little as a few seconds per part. Through this manufacturing process fully-formed precision parts needing minimal if any secondary finishing are easily produced in small, medium or large uniform batches.

The manufacturing process known as twin sheet thermoforming is similar to other vacuum forming processes but employs two sheets of thermoplastic material which inherently requires two molds be used as well. First, plastic sheets are unrolled or extruded before being mounted to separate frames and fed into a heater. Using electric, natural gas or infrared powered heating devices the temperature is raised to the point at which the material becomes soft and pliable. The temperature and duration may vary according to the specific properties of the polymer selected for a given part or component. Common materials include polyethylene, polypropylene, vinyl and acrylics. Still warm, the plastic sheets are simultaneously guided into a forming station where they are adhered to opposing female or concave molds. The molds are the inverse of the desired shape of the final product. A vacuum removes excess air within the mold, pulling the sheets towards their respective molds. The still impressionable forms are then pressed together. The sheets are fused creating a tight seal with a single seam around the edge. Cooling and drying the form in this position allows it to become rigid before reverse air ejects the part. If needed, secondary operations such as cutting, drilling or grinding are employed to remove excess material from the part.